Folding devices of rotary presses which print, cut and fold printing web, for example, can fold paper in two folding modes, i.e., straight run or collect run.
The printing web, which is transported between a folding cylinder and cutting cylinder that rotate via a pair of nipping rollers, is cut to a desired length, and is thereby made into cut printed product.
The non-printing area of the paper slightly upstream from the cutting position is pierced by and held by pins which extend from the folding cylinder surface, and is progressively wound onto the fixed circumferential surface part of the folding cylinder due to the rotation of the folding cylinder. The folding cylinder undergoes an angular displacement by a predetermined angle, and whenever the approximate middle part of the wound, cut printed product reaches the nearest position to the downstream adjacent cylinder (jaw cylinder), folding blades project from the folding cylinder circumferential surface, push up the approximate middle part (the fold) of the cut printed product, and transfer it to a jaw mechanism provided on the circumferential surface of an adjacent cylinder (jaw cylinder) situated facing the folding blades (straight run).
Alternatively, the folding blades project from the folding cylinder circumferential surface, push up the approximate midpart (the fold) of the cut printed product, and transfer it to the jaw mechanism provided on the circumferential surface of the downstream adjacent cylinder (jaw cylinder) facing the folding blades on every other occasion when the approximate middle part of the cut printed product reaches the aforesaid nearest position (collect run). At the time of this transfer, the pins which held the leading edge of this cut printed product fall away from the circumferential surface of the folding cylinder circumferential surface, releasing the cut printed product.
However, in either of the above folding modes, if the timing with which the pins released the cut printed product was too early, the cut printed product was not fully advanced, and it creased or crumpled when it was transferred. Moreover, the position of the fold in the cut printed product could not be maintained constant.
Conversely, if the timing with which the pins released the cut printed product was too late, as the cut printed product was restrained by the pins, the pin holes in the cut printed product were enlarged and the paper tore.
The grip on the cut printed product by the jaw mechanism of the adjacent cylinder (jaw cylinder) was then inadequate, causing the paper to slip so that it was not transferred properly.
In order to prevent such problems, a device is needed to adjust the timing of the pins falling from the folding cylinder circumferential surface relative to the rising of the folding blades from the circumferential surface of the folding cylinder. Such a device is disclosed for example in Japanese Patent Publication No.46-10123 (Koho) and Japanese Patent Publication No.7-29726 (Koho).
In the timing adjustment of the projection of the folding blades and falling of the pins shown in Japanese Patent Publication No.46-10123 (Koho), engaging parts of helical gears are provided in the drive path of a pin action cam. One of these engaged helical gears is free to displace parallel to a rotating shaft, and the adjustment is performed by displacing this gear.
The pin action cam has the same rotation center as the rotation center of the folding cylinder, and has the same drive source as that of the folding cylinder. The pin action may be changed over between straight run and collect run by selectively changing over so that rotation is performed at either one of two predetermined rotation speed ratios relative to the rotation of the folding cylinder.
A cam follower is provided free to rotate via a cam follower shaft at the free end of an arm installed at the end of a pin action shaft parallel to the axis of the folding cylinder in the folding cylinder, and is made to come into contact with a cam surface of the aforesaid pin action cam.
The pin action cam rotates together with the rotation of the folding cylinder with a selected rotational speed ratio, and due to the displacement of the cam follower depending on this pin action cam, the pin action shaft displaces back and forth so that the pins attached to the cam action shaft rise and set on the circumferential surface of the folding cylinder.
As the folding cylinder rotates, the folding blades then either project from the circumferential surface of the folding cylinder on each occasion (straight run) or project from the circumferential surface of the folding cylinder on every other occasion (collect run) that the folding cylinder reaches a predetermined rotation phase.
However, the change-over of this projection operation is performed independently of the change-over of rotation speed ratio of the pin action cam (change-over between straight run and collect run of the pin action).
Specifically, this folding device comprises a mechanism which enables it to change the rotation phase of the driven side relative to the rotation of the drive side using the torsion angle of the teeth of the helical gear in the drive path for driving the rotation of the pin action cam. By controlling this mechanism, the rotation phase of the pin action cam is changed relative to the rotation of the folding cylinder having the same drive source, and the timing with which the pins fall from the circumferential surface of the folding cylinder relative to the projection of the folding blades, which project from the circumferential surface of the folding cylinder with a desired timing relative to the rotation of the folding cylinder, is adjusted.
Next, the timing adjustment with which the pins fall relative to the projection of the folding blades disclosed in Japanese Patent Laid-Open Hei 7-29726 (Koho), is made by providing a change-over mechanism in the drive path of the pin action cam. This mechanism, which changes over between stop and rotation of the pin action cam by connecting or disconnecting the drive path, comprises a helical gear which transmits the rotation of the drive source downstream when the drive path is connected and stops in a fixed state when the drive path is disconnected. A helical gear which engages with this helical gear is provided downstream in the drive path of the pin action cam such that it is free to displace parallel to its rotation axis. By displacing this gear, the pin action cam which is in the stop state can be made to undergo an angular displacement to change its phase, or the rotation phase of the driven side relative to the rotation of the drive side can be changed using the torsion angle of the teeth of the helical gear.
A pin action cam, which has the same rotation center as the rotation center of the folding cylinder and has the same drive source as the folding cylinder, can change over between straight run and collect run by selectively changing over between stop with a predetermined rotation phase, and rotation under a predetermined rotation speed ratio relative to the rotation of the folding cylinder.
A pin cam follower is installed free to rotate via a cam follower shaft at the free end of an arm provided on the end of the pin cam shaft parallel to the axis of the folding cylinder in the folding cylinder, and is brought into contact with the cam surface of the aforesaid pin action cam. Due to the displacement of the pin cam follower due to the pin action cam in the stop-state or which rotates with a predetermined rotation speed ratio relative to the rotation of the folding cylinder, the pin action shaft moves back and forth, and the pins connected to the pin action shaft rise and set on the circumferential surface of the folding cylinder.
At this time, folding blades project from the circumferential surface of the folding cylinder on each occasion (straight run) or project from the circumferential surface of the folding cylinder on every other occasion (collect run) that the folding cylinder attains a predetermined rotation phase as the folding cylinder rotates.
However, the change-over of this projection action is performed separately from the change-over between stop and rotation of the pin action cam (i.e., change-over between straight run and collect run of the pin action).
Specifically, this folding device comprises a mechanism which causes the pin action cam in the stop state to undergo an angular displacement to change its phase, or change the rotation phase of the driven side relative to the rotation of the drive side using the torsion angle of the teeth of the helical gear in the drive path for rotating the pin action cam.
By controlling this mechanism, the stop phase or rotation phase of the pin action cam is changed relative to the rotation of the folding cylinder having the same drive source, and the timing with which the pins fall on the circumferential surface of the folding cylinder relative to the projection of the folding blades from the circumferential surface of the folding cylinder, which project with a desired timing relative to the rotation of the folding cylinder, is adjusted.
Moreover, this adjustment can be performed regardless of whether the pin action cam has stopped or is rotating.
In both of the above references in the prior art, the folding mode may be changed over between collect run and straight run, and a mechanism is provided which can adjust the pin action timing relative to the folding blade action timing in both of these folding modes. However, when the folding modes were changed over (change-over between straight run and collect run), the change-over of the folding blade action and the change-over of the pin action had to be performed separately. Therefore, a change-over operation had to be performed twice.
In addition to this, as the change-overs were performed separately, there was a considerable risk that the folding device would be operated after forgetting to change over either the folding blades or pins, and this posed a great problem in managing the device.
In this regard, a device has been proposed to perform the folding mode change-over operation only once, wherein change-over of the folding blade action and change-over of the pin action are performed in one operation by the same mechanism whenever a change-over occurs between straight run and collect run, as shown in, for example, Japanese Patent Laid-Open 56-18500 (Koho).
This folding device comprises a pin action fixed cam and folding blade action fixed cam installed at a suitable interval. These two fixed cams are fixed such that they are concentric with the rotation center of the folding cylinder, cam surfaces being formed on their outer circumferences.
This folding device further comprises a pin action rotation cam and folding blade action rotation cam provided in a one-piece construction between these two fixed cams. The pin action rotation cam has a cam surface on its outer circumference, and the pins are changed over between straight run and collect run by the joint action of this cam and the aforesaid pin action fixed cam. The folding blade action rotation cam also has a cam surface on its outer circumference, and the folding blades are changed over between straight run and collect run by the joint action of this cam and the aforesaid folding blade action fixed cam.
As the pin action rotation cam and folding blade action rotation cam are provided in a one-piece construction, both rotation cams can be stopped simultaneously. Further, as they can be rotated simultaneously, straight run and collect run may be selectively changed over by stopping these cams with a predetermined rotation phase at the same rotation center as the rotation center of the folding cylinder (straight run), or rotating them under a predetermined rotation speed ratio relative to the rotation of the folding cylinder (collect run).
In this way, straight run and collect run can be selectively changed over.
This device further provides a pin cam follower and folding blade cam follower. The pin cam follower is provided free to rotate via a cam follower shaft at the free end of an arm installed at the end of a pin action shaft parallel to the axis of the folding cylinder in the folding cylinder, and is brought into contact with the cam surfaces of the aforesaid pin action fixed cam and pin action rotation cam. The folding blade cam follower is provided free to rotate via the cam follower shaft at the open end of an arm installed at the end of a folding blade action shaft parallel to the axis of the folding cylinder between two adjacent pin action shafts in the folding cylinder, and is brought into contact with the cam surfaces of the aforesaid folding blade action fixed cam and folding-blade action rotation cam. The two cam followers respectively displace according to these four cams including the aforesaid two fixed cams. As a result, the pin action shaft and folding blade action shaft move back and forth, and the pins connected to the pin action shaft and folding blades connected to the folding blade action shaft rise and set on the circumferential surface of the folding cylinder while maintaining a predetermined relation due to these cams.
When a change-over is performed between straight run and collect run, the action of both the pins and the folding blades can be changed over in one operation by changing over to either stop or rotation of the aforesaid two rotation cams formed in one piece.
However, in this folding device, unlike the folding devices of the aforesaid two examples, the timing of the rising and setting of the pins on the circumferential surface of the folding cylinder could not be adjusted relative to the projection of the folding blades from the circumferential surface of the folding cylinder.